An uninterruptible power supply (UPS) is an apparatus connected between a power source and a device to prevent outages and “spikes” of the power source from adversely affecting the performance of the device. A UPS has an internal battery to ensure that continuous power is provided to the device even if power from the power source is interrupted. A UPS typically provides backup battery power for at least several minutes, which in most cases is long enough to power the device until power from the power source is reestablished.
A UPS is of particular importance for point-of-sale (POS) systems. A UPS can protect an otherwise vulnerable POS system against brief power disturbances during retail transactions. A shutdown of a POS system not only inconveniences waiting customers, but also threatens the integrity of data (price, inventory, promotions, etc.) collected by modern POS systems. Modern POS systems often support several peripheral devices including, for example, printers, scanners, credit card/debit card terminals, all of which may be damaged during power fluctuations and outages.
There exist UPS systems for use in POS environments which provide only alternative current (AC) power. This can be problematic because some POS devices, such as printers, often require direct current (DC) power, and thus cannot be protected by available UPS systems.
There is a need for POS UPS systems that output both AC and DC power.